Nationally, expect some $478 billion in tax increases, touching nearly all Americans, because various federal tax cuts and breaks expire at year’s end. In most cases, these increases won’t be immediate.

“It will affect million upon millions of taxpayers,” said Eileen Brown, district manager in Los Angeles for H&R Block, the tax preparation firm. “They are looking at a smaller paycheck and many credits and deductions that will change or expire.”

Brown said there are 70 tax breaks that have not been renewed and all of them are on the table. If they are not renewed or extended the change could result in about a $4,000 tax increase for the average family.

Here are a few of many changes to watch on the income tax front if there is no deal:

How much would overall income taxes increase?

Once the Bush-era tax cuts expire, our tax rates will basically be set back to 2001 levels with rates of 15 percent, 28 percent, 31 percent, 36 percent and 39.6 percent.

About 88 percent of U.S. taxpayers would see their taxes increase by an average of $3,500 a year, says a study by the non-partisan Tax Policy Center.

If we slice it another way, taxes would jump $2,400 on average for families with incomes of $50,000 to $75,000, the tax center calculates. In San Diego County the biggest chunk of taxpayers fall into this category, accounting for 17 percent of households in 2011.

In San Diego County there are 1,061,056 households whose earned income and benefits in 2011 is included below:

77,048 - Less than $10,000

48,635 - $10,000 to $14,999

98,425 - $15,000 to $24,999

96,033 - $25,000 to $34,999

135,899 - $35,000 to $49,999

184,570 - $50,000 to $74,999

135,382 - $75,000 to $99,999

157,160 - $100,000 to $149,999

66,596 - $150,000 to $199,999

61,308 - $200,000 or more

Will payroll taxes go up?

Yes. For the past two tax years, employee contributions to the Social Security program were 4.2 percent, down from the usual rate of 6.2 percent. That 2 percent rise in payroll taxes would result in 160 million American wage earners seeing their tax bills increase by an average of $1,000. Experts say this translates to an average of about $67 less in take home pay each month.

What about taxes on investments

Those would rise, too. (Remember, the top income tax rate would go to 39.6 percent from 35 percent.) Dividends would be taxed as ordinary income, and the top capital gains rate would increase to 20 percent from 15 percent.

Estate tax

The number of families subject to estate taxes will increase if the threshold drops from estates worth more than $5.12 million (and currently taxed at 35 percent) to estates worth more than $1 million, which will be taxed at 55 percent.

“It will impact a lot of people. You don’t want to die until they fix it,” said Vicki Maluk, a certified financial planner and enrolled agent who runs American Financial and Tax in Tustin. “A lot of people have a million dollar life insurance policy and when life insurance is added to assets like a house and savings then hitting $1 million is nothing.”

Child and childcare tax credits

The child tax credit has provided up to $1,000 per qualifying child depending on the income of the household. It will decrease to $500 per child after the new year. The childcare tax credit will decrease from $3,000 per child and $6,000 per family to $2,400 per child and $4,800 per family.

“This is a true middle class credit and lower-income families also get a refundable portion,” Mulak said. “People will have to plan for it, maybe make adjustments in their deductions at work to make up for what they will pay.”

Tuition and fees deduction

This deduction is worth up to $4,000 and expired last year. Unless Congress acts it will not be available to 2012 tax filers. The American Opportunity credit, which provides up to $2,500 in breaks to college students will expire Monday. Ditto for the $250 deduction for teachers who spend on classroom supplies.

“With the economy soft, so many people have gone back to school and so they are entitled to that tuition and fees deduction,” said Brown of H&R Block. “That tax break would impact all income levels.”

What about the alternative minimum tax?

Millions more taxpayers will be introduced to the AMT than ever before if Congress does nothing.

More than 31 million taxpayers will be subject to the AMT in 2012 without congressional action, compared with 4.3 million last year, says the Tax Policy Center.

The AMT was conceived in 1969 as an alternative tax to ensure that the wealthiest taxpayers, even with their big deductions and loopholes, didn’t avoid paying income taxes. Congress passed a “patch” every year to adjust income triggers for the AMT because it was not written to adjust for inflation. Even so, each year, it has crept down into the middle class as wages increased with inflation over the years.

“If that patch isn’t done, AMT is going to kick in for 34 million more taxpayers,” Brown said. “It could mean an additional tax bill of $3,000. AMT is a huge one.”

Taxpayers must calculate their liability under the AMT and the regular tax and pay whichever is greater. In 2011 the AMT exemption was $74,450 for married taxpayers and $48,450 for individuals. If there is no patch it would drop to pre-2001 levels of $45,000 for married taxpayers and $33,750 for singles.

Here’s more at stake — jobless benefits

Some 2 million jobless Americans may lose their federal unemployment aid. In San Diego County, more than 29,000 residents stand to lose their weekly unemployment checks after Dec. 29 no matter how many weeks they have left on their federal extensions because they have already surpassed the standard 26 weeks.

At one point, an unemployed person could receive the benefit for up to 99 weeks, based on a combination of federal government extensions. The extensions began in 2008 as a response to the Great Recession.

The state Employment Development Department estimates that 360,000 Californians are currently on the extensions.

Won’t all these tax increases throw us into a recession?

It will at least slow us down.

“The most significant impacts will occur to households that can least afford it, middle and lower income households,” said Marney Cox, economist for the San Diego Regional Association of Governments.

Because San Diego is a high cost of living area, households with little discretionary income may find it difficult to absorb the higher taxes and prices without sacrificing their standard of living,” Cox said.

Alan Gin, economist at the University of San Diego, said the impact will not hit all at once but will be spread out over time.

“In addition to the domestic cuts, there are cuts to military expenditures that could impact us in terms of personnel and contractors,” Gin said. “It will take money out of people’s pockets. It’s less money to spend, which will hurt initially.”